Temperature-dependent volume fraction of polar nanoregions in lead-free ( 1 − x ) ( B i 0.5 N a 0.5 ) Ti O 3 − x BaTi O 3 ceramics
Temperature-dependent volume fraction of polar nanoregions in lead-free ( 1 − x ) ( B i 0.5 N a 0.5 ) Ti O 3 − x BaTi O 3 ceramics
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DOI：
10.1103/physrevb.95.024104
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发表时间：
2017-01
影响因子：
3.7
通讯作者：
Malte Vögler;N. Novak;F. H. Schader;J. Rödel
中科院分区：
文献类型：
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作者：
Malte Vögler;N. Novak;F. H. Schader;J. Rödel
弛豫铁电体中的极性纳米区(PNR)的形成和温度演化是一个有趣的问题，目前仍在争论中。因此，我们以弛豫铁电体(1−x)(Bi0.5Na0.5)TiO_3-xBaTiO_3(BNT-xBT)为例，给出了一种估算PNR体积分数的方法。利用复合模型对极化和未极化样品在25◦C和800◦C温度下的杨氏模数与PNR的温度演化进行了详细的分析，杨氏模数对微小的结构扭曲高度敏感。PNR的提取体积分数和先前建议的伯恩斯温度以上的杨氏模量的增加表明，PNR的形成不是在定义的温度下发生的，而是在大约∼720◦C左右的较宽的温度范围内形成的。
The formation and temperature evolution of polar nanoregions (PNRs) in relaxor ferroelectrics is an intriguing issue that is still under debate. Therefore, we present an approach to estimate the volume fraction of PNRs by the example of the relaxor ferroelectric, (1 − x)(Bi0.5Na0.5)TiO3-xBaTiO3 (BNT-xBT). A detailed analysis of the Young’s modulus, which is highly sensitive to small structural distortions, at temperatures 25 ◦C< T <800 ◦C for both poled and unpoled samples, is correlated to the temperature evolution of PNRs by utilizing a composite model. The extracted volume fraction of the PNRs and the increasing Young’s modulus above the formerly suggested Burns temperature indicate that the formation of the PNRs does not occur at a defined temperature but rather in a broad temperature range starting around ∼720 ◦C.